CN105865741A - Simple method for measuring deflection angle of cross flow of wind tunnel test section - Google Patents

Abstract

The invention discloses a simple method for measuring a deflection angle of a cross flow of a wind tunnel test section, and aims at solving problems that a conventional method is larger in test vehicle number, is higher in cost and is complex in state. The main idea of the method is that model wings serve as the action surfaces of lateral forces, so the load is large, the measurement precision of the lateral forces is high and the disturbance on an incoming flow from a supporting mechanism is avoided. During data processing, the method enables a balance shaft system force (torque) vector to be converted into a model body shaft system or an air flow coordinate system. After conversion, the method carries out the interpolation of a basic longitudinal rising force-attack angle curve at lateral force positions after the forwarding and reverse rotation of a model. The method can obtain the deflection angle of the cross flow as quickly as possible on the basis of good accuracy and reliability, so as to facilitate the analysis of the impact on a testing result from flow field uniformity balance and the deflection angle of the cross flow. Moreover, the method is better in application prospect.

Description

A kind of simple and easy method measuring test chamber crossflow drift angle

Technical field

The present invention relates to aerodynamic scope, especially experimental aerodynamics field, be specially one and survey The simple and easy method of amount test chamber crossflow drift angle.

Background technology

The field of direction as one of key index in Flow Field in Wind Tunnel quality, be examination Flow Field in Wind Tunnel quality qualified with No major criterion.The uneven experimental error caused of the field of direction is systematic error, and it will not in repeatability by mistake Difference reflects, it should raising flow field uniformity, to reduce this error, manages to be modified it simultaneously.

GJB " high-speed wind tunnel and low-speed wind tunnel flow quality standard " according to air-flow drift angle at a high speed The interference volume of fighter plane resistance coefficient gives the index of air-flow drift angle, test section model district less than 1% calculating, Point out: longitudinal air flow drift angle must should be revised during more than 0.1 °, the flow field of more than 0.3 ° within 0.3 ° It is underproof.Crossflow drift angle mainly affects side force, and index is identical with longitudinal air flow drift angle.

The main method obtaining test chamber air-flow drift angle is by model positive and negative dress contrast test, utilizes Lift-angle of attack curve (side force-yaw angle curve) is asked for indulging (horizontal) to air-flow drift angle (as shown in Figure 1). The air-flow drift angle that the method is asked for reflects model lifting surface (side force face) regional testing section air-flow deflection feelings Condition, preferable for curve linear section correction effect, therefore, the method is the most domestic and international wind tunnel test mechanism Carry out the Main Means of airflow direction inhomogeneities correction.

But, most wind-tunnel have only carried out the measurement of longitudinal air flow drift angle, and horizontal mobility direction is unknown, Certain impact is brought to test data analyzer.It main reason is that, utilizes traditional method to carry out crossflow Measurement of angle needs to obtain the side force-yaw angle curve under the conditions of the positive and negative dress of model, and major part wind-tunnel Test section support system limits due to structural condition, does not has the yaw angle ability that becomes continuously, and each Mach Number state at least needs 6 startups could obtain crossflow drift angle (as shown in Figure 2,3), the longest, Cost is high, and needs frequently to change model state, the crossflow drift angle obtained due to model state difference Accuracy is the highest.

Summary of the invention

The goal of the invention of the present invention is: when carrying out crossflow measurement of angle for using existing method, deposit Problem at test more, relatively costly, the state complex of train number etc., it is provided that a kind of measurement test chamber is horizontal Simple and easy method to air-flow drift angle.The present invention, on the basis of accurate, reliable, can obtain crossflow as early as possible Drift angle index, is beneficial to flow field uniformity and weighs and the impact analysis to result of the test of the crossflow drift angle, tool There is preferable application prospect.

To achieve these goals, the present invention adopts the following technical scheme that

A kind of simple and easy method measuring test chamber crossflow drift angle, comprises the steps:

The first step, employing measure or the method for interrogation model data base, it is thus achieved that model longitudinal air flow drift angle Δ α_cp；

Second step, longitudinally substantially lift-angle of attack curve is carried out the correction of longitudinal air flow drift angle, it is thus achieved that benchmark is indulged To C_L-α curve, benchmark longitudinal direction C_LThe correction formula (1) of the α of-α curve is as follows:

$\mathrm{\α}=arctan\left(\frac{tan({\mathrm{\α}}_M+{\mathrm{\Δ\α}}_{CP})+tan\left({\mathrm{\Δ\α}}_e\right)cos\left({\mathrm{\Δ\β}}_e\right)}{cos\left({\mathrm{\Δ\β}}_e\right)-tan({\mathrm{\α}}_M+{\mathrm{\Δ\α}}_{CP})tan\left({\mathrm{\Δ\α}}_e\right)}\right)---\left(1\right);$

3rd step, ensure that Model angle of attack is zero, by model with balance around a rod axis with turning 90 °, with tulwar Mechanism, for becoming yaw angle mechanism, carries out determining the angle of attack and becomes yaw angle experiment, it is thus achieved that C during zero angle of wing plate angle of attack_L-beta curve, profit Model balance is asked for zero-incidence, the lift coefficient of zero yaw angle when turning 90 ° with least square fitting C_L+|_β=0；

4th step, ensure that Model angle of attack is zero, by model with balance around a rod axis with going to-90 °, with curved Cutter mechanism, for becoming yaw angle mechanism, carries out determining the angle of attack and becomes yaw angle experiment, it is thus achieved that C during zero angle of wing plate angle of attack_L-beta curve, Least square fitting is utilized to ask for model balance with zero-incidence, the lift coefficient of zero yaw angle when turning-90 ° C_L-|_β=0；

5th step, the lift coefficient C that the 3rd step is obtained_L+|_β=0, the lift coefficient C that obtains of the 4th step_L-|_β=0 Bring benchmark longitudinal direction C of second step into_LIn-α curve, respectively obtain zero liter of yaw angle Δ β under rotating forward state_0U、 Zero liter of yaw angle Δ β under inverted status_0D, finally use equation below (2) to obtain current Mach number state The crossflow drift angle Δ β of lower test section_cp:

Δβ_cp=0.5 × (Δ β_0D-Δβ_0U) (2)。

In described formula (1), α_MRefer to test fuselage (or structure during the non-stand under load of nominal angle of attack, i.e. model Make line) angle；Δα_cpRefer to the model longitudinal air flow drift angle obtained by the first step；Δα_eRefer to be carried by balance The model longitudinal elasticity angle that lotus and mechanism's elastic angle formula obtain；Δβ_eRefer to by balance load and mechanism elastic The model transverse elasticity angle that angle formula obtains.Benchmark longitudinal direction C_L-α curve refers to carry out conventional longitudinal data The C that longitudinal air flow drift angle obtains after revising_L-α ' curve.

In the first step, assay method is used to obtain model longitudinal air flow drift angle Δ α_cpStep as follows:

A balance is arranged in model by (), then by model routine formal dress, it is thus achieved that model longitudinally substantially rises Power-angle of attack curve, the angle of attack is according to equation below (3) matching test data:

C_L=C_L0+C_L ^αα (3),

Zero liter of angle of attack Δ α of formal dress model is obtained again with method of least square_0U；

B model and balance are turned 180 ° around a rod axis by (), it is thus achieved that anti-die-filling type lift-angle of attack curve, Obtain zero liter of angle of attack Δ α of anti-die-filling type_0D；

C () uses equation below (4) to obtain this model longitudinal air flow drift angle Δ α under test Mach number_cp:

Δα_cp=0.5 × (Δ α_0D-Δα_0U) (4)。

In described step a, C_LFor the lift coefficient of model, α is Model angle of attack, C_L0For model zero-incidence Time lift coefficient, i.e. the intercept of lift-angle of attack curve；C_L ^αFor slope of lift curve, i.e. lift-angle of attack curve Slope.

In described step a, conventional formal dress refer to model ventral down, head forward, and dries according to routine Mode is tested.Specifically, in experimentation, conventional formal dress refer to model ventral down, head Forward, and according to routine blowing mode carry out determining Mach number, yaw angle becomes angle of attack experiment.

In described step a, balance is arranged in model, then by model routine formal dress, it is thus achieved that model base This longitudinal direction lift-angle of attack curve, matching test data in the range of the angle of attack [-2 °, 2 °].

Tradition crossflow measurement of angle method utilizes the side force of the generations such as model fuselage, vertical tail to survey Amount, in addition to aforesaid drawbacks, surveyed crossflow drift angle actually contains turns head, supporting mechanism etc. to flowing Inductive effect, the flow field deflection situation of untrue reflection region, model side force face sky wind-tunnel.Use and pass The crossflow drift angle that system method records can be compared with accurately revising conventional Low Angle Of Attack horizontal course test data, but nothing Method accurate evaluation Flow Field in Wind Tunnel uniformity.

In this application, applicant thinks after analyzing, and conventional wind-tunnel is equipped with fan-shaped tulwar support mostly, longitudinally During operation less to the disturbance flowed, therefore, the present invention uses model along supporting mechanism axis forward and backward 90 ° Crossflow is measured in (i.e. around supporting mechanism axis both clockwise half-twist, counter-clockwise half-twist) blowing Drift angle.The main thought of the present invention is as follows: utilizing model wing as the acting surface of side force, its load is big, The measurement precision of side force is high, avoids the supporting mechanism disturbance to flowing simultaneously.Carrying out data process Time, the present invention by balance axle system power (square) vector median filters to model body axle system or air path axis system；After conversion, To longitudinally substantially lift-angle of attack curve interpolation at side force after model forward and backward, it is thus achieved that positive and negative fill right The lateral angles answered.

Use the present invention need to obtain in advance the longitudinally substantially curve of model, this longitudinally substantially curve mainly pass through Acquisition, tool are revised in model deadweight correction, balance-support system angular flexibility correction and longitudinal air flow drift angle When gymnastics is made, this model longitudinal air flow drift angle under test Mach number to be obtained in advance, thus, it is only required to want 4 startups can obtain crossflow drift angle.Mach number flow field is specified if model database has had Longitudinal air flow drift angle data, then, when crossflow measurement of angle, start train number and be reduced to 2 times.

In described step b, model and balance are turned 180 ° around a rod axis, it is thus achieved that anti-die-filling type lift- Angle of attack curve, utilizes same procedure to ask for zero liter of angle of attack Δ α of anti-die-filling type_0D。

In third and fourth step, it is ensured that Model angle of attack is zero, by model with balance around a rod axis same turn+90 °, Referring to ensure that bent blade mechanism is constant, rotating 90 ° around a rod axis, model ventral is towards a left side；Ensure Model angle of attack Being zero, by model, around propping up, rod axis is same goes to-90 ° with balance, refers to ensure that bent blade mechanism is constant, around pole Axis rotates-90 °, and model ventral is towards the right side.If carrying out similar passenger plane, transporter class buttock afterbodies Experiment, pole is with pre-drift angle α_sWhen turning, then the lift coefficient C of forward and backward zero yaw angle asked for_L±|_β=0 Referring to that corresponding Model angle of attack is the pre-drift angle of pole+longitudinal elasticity angle, yaw angle is the lift coefficient of zero state. Owing to using model coordinate systems, pole pre-drift angle α_sDisappeared when computing formula (3), used this side Formula carries out forward and backward experiment, double rotating shaft can not be used to turn head, it is to avoid model state replacing (just ensureing, After reversion, Model angle of attack is zero) deviation brought.

As it was previously stated, use the present invention can effectively reduce the number of times starting train number, reduce experimental cost, greatly Width improves the test efficiency of crossflow measurement of angle；Meanwhile, can be effectively improved crossflow inclined for the present invention The measurement accuracy at angle, improves the accuracy of measurement result.

Accompanying drawing explanation

Examples of the present invention will be described by way of reference to the accompanying drawings, wherein:

Fig. 1 is test section air-flow measurement of angle schematic diagram.

Fig. 2 is different yaw angle state side force-angle of attack curve charts.

Fig. 3 is side force-yaw angle curve chart that button point obtains.

Fig. 4 is that in embodiment 1, TY-154 marks mould positive and negative dress C_L-α curve chart.

Fig. 5 is that in embodiment 1, TY-154 marks mould forward and backward 90 DEG C_L-beta curve figure.

Fig. 6 is that in embodiment 1, crossflow drift angle figure is asked in matched curve.

Detailed description of the invention

All features disclosed in this specification, or disclosed all methods or during step, except mutually Beyond the feature repelled mutually and/or step, all can combine by any way.

Any feature disclosed in this specification, unless specifically stated otherwise, all can by other equivalence or have similar The alternative features of purpose is replaced.I.e., unless specifically stated otherwise, each feature is a series of equivalence or class Like an example in feature.

Embodiment 1

The present invention obtains the C of correspondence respectively by the method for model forward and backward 90 °_L-beta curve, utilizes curve Corresponding zero liter of yaw angle is asked in matching, calculates finally by formula, obtains crossflow drift angle Δ β_cp。

Realize especially by following data processing method.

As a example by 2.4 meters of transonic wind tunnel TY-154 calibration model tests, just passing through during free stream Mach number 0.74, Anti-die-filling type records C_L-α curve is as shown in Figure 4.Least square fitting is utilized to try to achieve zero liter of angle of attack of formal dress Δα_0U, counter fill zero liter of angle of attack Δ α_0DIt is respectively 0.105 °, 0.245 °, utilizes equation below Δα_cp=0.5 × (Δ α_0D-Δα_0U), obtain this model longitudinal air flow drift angle Δ α under test Mach number_cp:

Δα_cp=0.5 × (0.245 °-0.105 °)=0.070 °.

Then, equation below is used(α_MRefer to reality Test nominal angle of attack, i.e. fuselage (or structure line) angle during the non-stand under load of model；Δα_cpRefer to be obtained by the first step The model longitudinal air flow drift angle obtained；Δα_eRefer to that the model obtained by balance load and mechanism's elastic angle formula is indulged To angular flexibility；Δβ_eRefer to the model transverse elasticity angle obtained by balance load and mechanism's elastic angle formula.Base Accurate longitudinal C_LThe C that-α curve obtains after referring to conventional longitudinal data is carried out the correction of longitudinal air flow drift angle_L-α ' is bent Line.), it is calculated the angle of attack value after revising longitudinal air flow drift angle and see table shown in 1.

Table 1 result of calculation

Benchmark longitudinal direction C is obtained after correction_L-α curve fitting formula is as follows:

C_L=0.099 α-0.0174 (5)；

Model and balance are turned+90 ° ,-90 ° around a rod axis, the C obtained during free stream Mach number 0.74_L-β Curve is as shown in figure (5).Utilizing least square fitting, (i.e. model and balance are around propping up to try to achieve rotating forward 90 ° Rod axis turns+90 °), reversion 90 ° (i.e. model and balance turns-90 ° around a rod axis) time zero-incidence, zero side The lift coefficient at sliding angle is respectively C_L+|_β=0=0.0018, C_L-|_β=0=-0.0104.

By the lift coefficient C of zero-incidence, zero yaw angle when rotating forward 90 °_L+|_β=0, and reversion 90 ° time zero-incidence, The lift coefficient C of zero yaw angle_L-|_β=0Bring model reference longitudinal direction C into_L-α curve fitting formula is (i.e. C_L=0.099 α-0.0174) in, try to achieve zero liter of yaw angle under model forward and backward state respectively Δβ_0U=0.194 °, Δ β_0D=0.071 °.

Finally, by Δ β_0U、Δβ_0DSubstitution formula: Δ β_cp=0.5 × (Δ β_0D-Δβ_0UIn), as shown in Figure 6, When trying to achieve free stream Mach number 0.74, TY-154 mark mould crossflow drift angle is:

Δβ_cp=0.5 × (0.071 °-0.194 °)=-0.062 °.

Relative to prior art, the present invention can effectively reduce startup train number, reduces experimental cost, meanwhile, It is effectively improved the measurement accuracy of crossflow drift angle, improves the accuracy of measurement result.

The invention is not limited in aforesaid detailed description of the invention.The present invention expand to any in this manual Disclose new feature or any new combination, and disclose arbitrary new method or the step of process or any New combination.

Claims (6)

1. the simple and easy method measuring test chamber crossflow drift angle, it is characterised in that comprise the steps:

The first step, employing measure or the method for interrogation model data base, it is thus achieved that model longitudinal air flow drift angle Δ α_cp；

Second step, longitudinally substantially lift-angle of attack curve is carried out the correction of longitudinal air flow drift angle, it is thus achieved that benchmark longitudinal direction C_L-α Curve, benchmark longitudinal direction C_LThe correction formula (1) of the α of-α curve is as follows:

$\mathrm{\α}=arctan\left(\frac{tan({\mathrm{\α}}_M+{\mathrm{\Δ\α}}_{CP})+tan\left({\mathrm{\Δ\α}}_e\right)cos\left({\mathrm{\Δ\β}}_e\right)}{cos\left({\mathrm{\Δ\β}}_e\right)-tan({\mathrm{\α}}_M+{\mathrm{\Δ\α}}_{CP})tan\left({\mathrm{\Δ\α}}_e\right)}\right)---\left(1\right);$

3rd step, ensure that Model angle of attack is zero, by model with balance around a rod axis with turning 90 °, with bent blade mechanism For becoming yaw angle mechanism, carry out determining the angle of attack and become yaw angle experiment, it is thus achieved that C during zero angle of wing plate angle of attack_L-beta curve, utilizes Little square law matching asks for model balance with zero-incidence, the lift coefficient C of zero yaw angle when turning 90 °_L+|_β=0；

4th step, ensure that Model angle of attack is zero, by model with balance around a rod axis with going to-90 °, with knives bending machine Structure, for becoming yaw angle mechanism, carries out determining the angle of attack and becomes yaw angle experiment, it is thus achieved that C during zero angle of wing plate angle of attack_L-beta curve, utilizes Least square fitting asks for model balance with zero-incidence, the lift coefficient C of zero yaw angle when turning-90 °_L-|_β=0； 5th step, the lift coefficient C that the 3rd step is obtained_L+|_β=0, the lift coefficient C that obtains of the 4th step_L-|_β=0Bring into Benchmark longitudinal direction C of second step_LIn-α curve, respectively obtain zero liter of yaw angle Δ β under rotating forward state_0U, anti- Turn zero liter of yaw angle Δ β under state_0D, finally use equation below (2) to obtain under current Mach number state The crossflow drift angle Δ β of test section_cp:

Δβ_cp=0.5 × (Δ β_0D-Δβ_0U) (2)。

The most according to claim 1, measure the simple and easy method of test chamber crossflow drift angle, its feature exists In, in described formula (1), α_MRefer to test fuselage (or structure during the non-stand under load of nominal angle of attack, i.e. model Make line) angle；Δα_cpRefer to the model longitudinal air flow drift angle obtained by the first step；Δα_eRefer to be carried by balance The model longitudinal elasticity angle that lotus and mechanism's elastic angle formula obtain；Δβ_eRefer to by balance load and mechanism elastic The model transverse elasticity angle that angle formula obtains.

The simple and easy method of measurement test chamber crossflow drift angle the most according to claim 1 or claim 2, its feature It is, in the first step, uses assay method to obtain model longitudinal air flow drift angle Δ α_cpStep as follows:

A balance is arranged in model by (), then by model routine formal dress, it is thus achieved that model longitudinally substantially lift-attack Angular curve, the angle of attack is according to equation below (3) matching test data:

C_L=C_L0+C_L ^αα (3),

Zero liter of angle of attack Δ α of formal dress model is obtained again with method of least square_0U；

B model and balance are turned 180 ° around a rod axis by (), it is thus achieved that anti-die-filling type lift-angle of attack curve, obtain Zero liter of angle of attack Δ α of anti-die-filling type_0D；

C () uses equation below (4) to obtain this model longitudinal air flow drift angle Δ α under test Mach number_cp:

Δα_cp=0.5 × (Δ α_0D-Δα_0U) (4)。

The most according to claim 3, measure the simple and easy method of test chamber crossflow drift angle, its feature exists In, in described step a, C_L0For lift coefficient during model zero-incidence, the i.e. intercept of lift-angle of attack curve； C_L ^αFor slope of lift curve, i.e. lift-angle of attack slope of a curve.

5. according to the simple and easy method of measurement test chamber crossflow drift angle, its feature described in claim 3 or 4 Be, in described step a, conventional formal dress refer to model ventral down, head forward, and blows according to routine Wind mode is tested.

6. according to the simple and easy method of measurement test chamber crossflow drift angle described in any one of claim 1～6, It is characterized in that, in described step a, balance is arranged in model, then by model routine formal dress, obtain Obtain model longitudinally substantially lift-angle of attack curve, matching test data in the range of the angle of attack [-2 °, 2 °].